A novel feature space monitoring index of salinisation in the Yellow River Delta based on SENTINEL‐2B MSI images

Abstract

AbstractMost of previous studies utilized the surface parameters from LANDSAT images to construct the feature space monitoring index model of salinisation (salinization), and a few studies that have combined the feature space model with SENTINEL‐2B MSI images have been reported. In addition, the red edge index derived from SENTINEL‐2B MSI images can provide more detailed information to indicate the vegetation condition when monitoring salinized land ecosystems. Based on SENTINEL‐2B MSI images, this paper introduces seven typical parameters, namely NDVI, MSAVI, SI, Albedo, NDre1, NDre2, and NDre3 (red edge index) to construct two category features space models (point‐to‐line type and point‐to‐point type), and then, a novel salinisation monitoring index for use in the Yellow River Delta (YRD). Our main conclusions showed that: (1) the monitoring index model based on SENTINEL‐2B MSI images and a feature space model has high applicability for the salinisation monitoring in the YRD, with an average precision of R2 = 0.8499; (2) the point‐to‐point monitoring index of soil salinisation based on the NDre1‐SI feature space model has the best inversion accuracy of R2 = 0.9305 and RMSE = 0.9926; (3) the red edge index can better indicate the state and evolution process of soil salinisation. The salinisation monitoring models that included the red edge indexes have higher inversion accuracy with an average value of R2 = 0.8650; (4) the soil salinisation in the YRD was more serious in its eastern and northeastern regions than other parts. The results provide a new technical and methodological approach for the prevention and treatment of regional salinisation.